OBJECTIVETo investigate the transduction ability of PEP-1-CAT fusion protein into human umbilical vein endothelial cell (HUVECs) and the effects on hydrogen-peroxide (H2O2)-induced oxidative stress injury in these cells.

METHODSWith the use of TA-cloning program and isocaudamer technique, the pET15b-PEP-1-CAT of prokaryotic expression plasmid was successfully constructed. The recombinant plasmid was transformed into E.coli BL21 (DE3) and the protein expression was induced by IPTG. The recombinant protein has an N-terminal His-tag which could be used to purify the target protein by affinity chromatography on a Ni2+-NTA-resin column. The fusion protein PEP-1-CAT was prepared and confirmed by specific enzyme activity in vitro. The purified PEP-1-CAT fusion protein was added on cultured HUVECs in vitro. The transduction ability of PEP-1-CAT fusion protein into cells was analyzed by Western blot and specific enzyme activity. The cells were treated with H2O2 (0.5 mmol/L) alone and in combination with PEP-1-CAT fusion protein for 4 h. Then, the cell viability, lactate dehydrogenase (LDH) and malondialdehyde (MDA) contents were measured.

RESULTSThe PEP-1-CAT fusion protein could be transduced into the cultured HUVECs in a dose- and time-dependent manner and be stable for at least 48 h. After H2O2 administration, cell viability was significantly reduced compared with control group (37.23%+/-5.68% vs. 100%, P<0.05), while LDH leakage (849.3 U/L+/-95.1 U/L) and MDA (8.23 nmol/L+/-1.58 nmol/L) content were significantly higher than that in control group (540.6 U/L+/-65.7 U/L and 2.46 nmol/L+/-1.42 nmol/L, respectively, all P<0.05). Preincubation with PEP-1-CAT proteins at various concentrations (0.25-2 micromol/L) significantly attenuated H2O2-induced cell injury.

CONCLUSIONThe PEP-1-CAT fusion protein could efficiently penetrate HUVECs and the transduced protein could attenuate cellular oxidative stress injury induced by H2O2. The PEP-1-CAT fusion protein might be a new strategy for preventing and treating oxidative stress induced diseases.

Catalase ; metabolism ; Cells, Cultured ; Cysteamine ; analogs & derivatives ; metabolism ; Endothelial Cells ; metabolism ; Humans ; Hydrogen Peroxide ; Oxidative Stress ; physiology ; Peptides ; metabolism ; Umbilical Veins ; cytology

OBJECTIVETo investigate the penetrating ability of fusion protein PEP-1-EGFP with human umbilical vein endothelial cells.

METHODSTwo prokaryotic expression plasmids pET15b-EGFP and pET15b-PEP-1-EGFP were constructed and transformed into E. coli BL21 (DE3) to express EGFP and fusion protein PEP-1-EGFP, respectively. The expressed EGFP and PEP-1-EGFP were purified with Ni(2+) -resin affinity chromatography, and their capabilities of transduction into human umbilical vein endothelial cells were evaluated. The time- and dose-dependent transduction of the fusion protein PEP-1-EGFP and its stability in the human umbilical vein endothelial cells were observed. The toxicity of the fusion protein PEP-1-EGFP was detected by MTT method.

RESULTSEGFP failed to be transduced into human umbilical vein endothelial cells, whereas PEP-1-EGFP fusion protein was transduced into cells shortly in 5 minutes. Its transduction was time- and dose-dependent and the fluorescence in the cells were detected even 27 hours later. No cytotoxicity of the fusion protein PEP-1-EGFP to human umbilical vein endothelial cells was detected even when the dose reached up to 200 micromol/L.

CONCLUSIONPEP-1-EGFP fusion protein can efficiently transduce the target protein into human umbilical vein endothelial cells, which provides a basis for future researches on the transduction of antioxidant enzymes mediated by the cell-penetrating peptide, PEP-1, in ischemia-reperfusion injury therapy.

Cells, Cultured ; Cysteamine ; analogs & derivatives ; metabolism ; Endothelial Cells ; drug effects ; metabolism ; Green Fluorescent Proteins ; metabolism ; Humans ; Peptides ; metabolism ; Protein Transport ; Recombinant Fusion Proteins ; metabolism ; toxicity ; Umbilical Veins ; cytology

OBJECTIVETo construct prokaryotic expression vector of pET15b-PEP-1-SOD1 and investigate whether PEP-1-SOD1 fusion protein could be transduced into human umbilical vein endothelial cells (HUVECs) and the effects on hypoxia/reoxygenation injury.

METHODSThe recombinant plasmids pET15b-SOD1 and pET15b-PEP-1-SOD1 were constructed and transformed into E. coli BL21 (DE3) to express SOD1 and PEP-1-SOD1 with an N-terminal His-tag. The purified SOD1 and PEP-1-SOD1 were incubated with HUVECs and the viability (MTT assay) and the release of lactate dehydrogenase (LDH) in culture medium were determined in the hypoxia/reoxygenation injury model. The morphological changes were observed under an inverted phase contrast microscope. The content of malondialdehyde (MDA) in HUVECs was also determined with the method of thiobarbituric acid.

RESULTSPEP-1-SOD1 fusion protein could be transduced into cultured HUVECs in a time- and dose-dependent manner. The intracellular enzymatic activity of PEP-1-SOD1 after 30 min incubation with HUVECs was significantly higher than control group (60.88 U/ml +/- 6.73 U/ml vs. 41.06 U/ml +/- 4.19 U/ml, P < 0.01). The transduced PEP-1-SOD1 protein was enzymatically stable for 24 h within cells. After hypoxia/reoxygenation injury, control HUVECs shrunk, became round-shaped and intercellular space increased, while these morphological changes were not observed in PEP-1-SOD1 transduced HUVECs. PEP-1-SOD1 transduction also markedly increased the viability, decreased LDH leakage into culture media and reduced the content of MDA post hypoxia/reoxygenation.

CONCLUSIONSPEP-1-SOD1 fusion protein could be efficiently transduced into HUVECs in a natively active form, and the delivered enzymatically active PEP-1-SOD1 exhibits cellular protection against hypoxia/reoxygenation injury in HUVECs. The transduction of SOD1 mediated by cell-penetrating peptide, PEP-1, provides a basis for further research on the prevention of ischemia/reperfusion injury in vivo.

Cell Hypoxia ; Cells, Cultured ; Cysteamine ; analogs & derivatives ; metabolism ; Endothelial Cells ; cytology ; Humans ; Malondialdehyde ; metabolism ; Peptides ; genetics ; metabolism ; Recombinant Fusion Proteins ; genetics ; metabolism ; Reperfusion Injury ; prevention & control ; Superoxide Dismutase ; genetics ; metabolism ; Transduction, Genetic ; Umbilical Veins ; cytology

OBJECTIVETo investigate the transduction efficiency of purified PEP-1-CAT fusion protein into rat heart and the protective effect of the fusion protein against myocardial ischemia-reperfusion injury.

METHODSPEP-1-CAT or CAT (500 microg) was injected in SD rats via the caudal vein, using normal saline as the control, and the hearts were harvested at 0.5, 1, 2, 4, 8, and 24 h after the injection. The transduction efficiency was evaluated by immunofluorescence technique, and the CAT activity was measured. Forty rats were randomized into 5 groups, namely the sham-operated group, ischemia-reperfusion group, and 3 PEP-1-CAT -treated groups (100, 300, and 500 microg). The left main coronary artery was occluded for 1 h followed by a 2-h reperfusion, and at the end of reperfusion, serum LDH and CK and MDA content in the myocardium were measured.

RESULTSNo green fluorescence was observed in saline group or CAT group. Bright green fluorescence was observed in PEP-1-CAT groups at different time points, most conspicuous at 8 h. No significant difference in CAT activity was found between CAT group and saline group (P>0.05); with the lapse of time, CAT activity in PEP-1-CAT group increased gradually, reaching the peak level at 8 h, which was 4.2 folds of that in the saline group. LDH ,CK and MDA were significantly lower in PEP-1-CAT- groups than in ischemia-reperfusion group (P<0.01).

CONCLUSIONPEP-1 can mediate the transduction of CAT in rat heart in a time-dependent manner, and PEP-1-CAT preconditioning provides a protective effect against ischemia- reperfusion injury in rats.

Animals ; Catalase ; metabolism ; pharmacology ; Cysteamine ; analogs & derivatives ; metabolism ; pharmacology ; Ischemic Preconditioning, Myocardial ; Male ; Myocardial Reperfusion Injury ; metabolism ; pathology ; prevention & control ; Peptides ; metabolism ; pharmacology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Recombinant Fusion Proteins ; pharmacology ; Transduction, Genetic

Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is a tumor suppressor. Although it is well known to have various physiological roles in cancer, its inhibitory effect on inflammation remains poorly understood. In the present study, a human PTEN gene was fused with PEP-1 peptide in a bacterial expression vector to produce a genetic in-frame PEP-1-PTEN fusion protein. The expressed and purified PEP-1-PTEN fusion protein were transduced efficiently into macrophage Raw 264.7 cells in a time- and dose- dependent manner when added exogenously in culture media. Once inside the cells, the transduced PEP-1-PTEN protein was stable for 24 h. Transduced PEP-1-PTEN fusion protein inhibited the LPS-induced cyclooxygenase 2 (COX-2) and iNOS expression levels in a dose-dependent manner. Furthermore, transduced PEP-1-PTEN fusion protein inhibited the activation of NF-kappa B induced by LPS. These results suggest that the PEP-1-PTEN fusion protein can be used in protein therapy for inflammatory disorders.
Animals ; Cell Line ; Cyclooxygenase 2/*metabolism ; Cysteamine/*analogs & derivatives ; Enzyme Activation ; Humans ; Lipopolysaccharides/*pharmacology ; Macrophages/*metabolism ; Mice ; NF-kappa B/metabolism ; Nitric Oxide/*biosynthesis ; Nitric Oxide Synthase Type II/metabolism ; PTEN Phosphohydrolase/*genetics ; Peptides/*genetics ; Recombinant Fusion Proteins/*biosynthesis/genetics ; Signal Transduction

OBJECTIVETo construct the prokaryotic expression plasmid pET15b-PEP-1-CAT to obtain purified fusion protein of PEP-1-CAT.

METHODSUsing pfu DNA polymerase, the full-length human catalase cDNA was amplified by PCR from pZeoSV2(+)-CAT plasmid, and the PCR product was added with "A" using Taq DNA polymerase. The purified product of CAT cDNA with the base A at its 3' end was ligated with pGEM-T Easy vector and transformed into DH5alpha. The correct recombinant was identified by PCR and Sal I/Bgl II digestion and named as pGEM-T-CAT. Two oligonucleotides were synthesized and annealed to generate a double-stranded oligonucleotide encoding the PEP-1 peptide, which was directly ligated into Nde I/Xho I-digested pET15b. The recombinant plasmid was identified by double-enzyme digestion and named as pET15b-PEP-1. pET15b-PEP-1 and pGEM-T-CAT were further digested by Xho I/BamH I and Sal I/Bgl II, respectively. The purified linear fragment of pET15b-PEP-1 and CAT cDNA fragment were ligated using two pairs of isocaudarners possessing different recognition sequences but producing compatible cohesive ends. The clone with the expected insert was selected using Xho I restriction analysis followed by sequence analysis. The recombinant plasmid was transformed into E. coli BL21(DE3) which was induced by IPTG. The recombinant protein possessed an N-terminal His-tag sequence which could be used to purify the target protein by affinity chromatography on a Ni(2+)-NTA-resin column. The fusion protein PEP-1-CAT was produced and confirmed by specific enzyme activity in vitro.

RESULTSSequence analysis showed that the PEP-1 and the human CAT cDNA sequence of pET15b- PEP-1-CAT had identical sequence with designed PEP-1 peptide and human catalase cDNA sequence in GenBank (accession No. AY028632), respectively. SDS-PAGE and Western blotting confirmed successful expression and purification of PEP-1-CAT fusion protein with specific activity of 77.15 U/g.

CONCLUSIONThe prokaryotic expression plasmid pET15b-PEP-1-CAT has been constructed successfully, and the successful expression and purification of PEP-1-CAT provides a basis for prevention and therapy of various disorders related to oxidative stress.

Base Sequence ; Blotting, Western ; Catalase ; genetics ; metabolism ; Chromatography, Affinity ; Cloning, Molecular ; Cysteamine ; analogs & derivatives ; metabolism ; Electrophoresis, Polyacrylamide Gel ; Escherichia coli ; genetics ; metabolism ; Gene Expression ; Humans ; Molecular Sequence Data ; Peptides ; genetics ; metabolism ; Plasmids ; genetics ; Prokaryotic Cells ; metabolism ; Recombinant Fusion Proteins ; genetics ; isolation & purification ; metabolism

OBJECTIVETo construct the expression vector pET15b-pep-1-EGFP and purify the fusion protein PEP-1-EGFP expressed in E. coli BL21(DE(3)) for evaluating the cell-penetrating capability of the cell-penetrating peptide PEP-1.

METHODSTwo oligonucleotides encoding PEP-1 was synthesized and annealed to generate PEP-1-encoding DNA. The recombinant plasmid pET15b-pep-1-EGFP was constructed by inserting PEP-1-encoding DNA and enhanced green fluorescent protein (EGFP) cDNA into pET15b. The fusion protein PEP-1-EGFP expressed in E. coli BL21(DE(3)) was purified with Ni(2+)-resin affinity chromatography and transduced into human umbilical vein endothelial cells.

RESULTSSequence analysis confirmed successful construction of the expression vector pET15b-pep-1-EGFP, and the fusion protein PEP-1-EGFP was expressed and purified efficiently with a yield of approximately 14.15 mg/100 ml bacteria medium. SDS-PAGE and Western blotting identified the purified protein as PEP-1-EGFP, and the cell-penetration assay verified that the fusion protein could be transduced into human umbilical vein endothelial cells.

CONCLUSIONThe successful expression and purification of PEP-1-EGFP and its efficient transduction into human umbilical vein endothelial cells provides a basis for PEP-1-mediated biomacromolecular transduction in protein therapy.

Base Sequence ; Blotting, Western ; Cells, Cultured ; Cysteamine ; analogs & derivatives ; metabolism ; Electrophoresis, Polyacrylamide Gel ; Endothelial Cells ; cytology ; metabolism ; Green Fluorescent Proteins ; genetics ; metabolism ; Humans ; Microscopy, Fluorescence ; Molecular Sequence Data ; Peptides ; genetics ; metabolism ; Plasmids ; genetics ; Recombinant Fusion Proteins ; genetics ; metabolism ; Transfection ; Umbilical Veins ; cytology